[drizek]

On the subject of not having the headphones plugged in, on the Bottlehead forum there is a recommendation that the two unused prongs on the headphone jacks be wired to ground (picture in the link) to keep startup voltage at 0 (with no headphones plugged in). 
 
http://www.bottlehead.com/smf/index.php/topic,2946.0.html

 

[drizek]

So even after a couple days of burn in, I still get a lot of distortion from my amp. Is it time to call up Bottlehead and ask for a replacement tube, or is there something else that could be wrong with it?

 

[brunk]

  So even after a couple days of burn in, I still get a lot of distortion from my amp. Is it time to call up Bottlehead and ask for a replacement tube, or is there something else that could be wrong with it?

Check over your grounding

 

[lextek]

So even after a couple days of burn in, I still get a lot of distortion from my amp. Is it time to call up Bottlehead and ask for a replacement tube, or is there something else that could be wrong with it?

You might want to post this question on the forum at Bottlehead.com. Very, helpful folks there too. When I built mine had no noise so I don't think it will change with burn-in.

 

[drizek]

I've doen all the multimeter checks and they're all fine. Do you mean resolder?

 

[sjeffrey]

  I've doen all the multimeter checks and they're all fine. Do you mean resolder?

It's a good idea to have spares of both tubes, that way you can easily figure out if it's a tube problem or not.
If the noise is only when you tap on the tube then it's probably tube but you also said that some bass notes cause the problem so I would make sure all you solders are good.

 

[NightFlight]

I've doen all the multimeter checks and they're all fine. Do you mean resolder?

Grainger has a sticky thread at the top of the Crack forum at BH. A solid breakdown for ground checks. Here... I'll fetch it....

http://www.bottlehead.com/smf/index.php/topic,4812.0.html

I had heavy distortion at the outset, but mine disappeared with burn/break-in.

 

[drizek]

Thanks NightFlight.
 
There is one solder joint that I know is not that great. I was planning on fixing it when I did the speedball installation. 

 

[lugnut]

Well, no. I unplug it when not in use. And the tubes are relatively cheap stock ones. I have pairs for my Lyr which sell used for more than the value of the crack.


Hoping a nice 5998 will open the crack up a bit more.

Would you mind to comment a little on how the Crack vs Lyr sounds with the HD800 ?  Thanks

 

[Aeolus Kratos]

Here comes one of the hardest headphones to drive on planet

 

 

 

 

[Armaegis]

I think I tried that combo a long time ago but nothing sticks out in my memory...

 

[Mahdi8]

That looks sweet how does it sound?

 

[Aeolus Kratos]

  I think I tried that combo a long time ago but nothing sticks out in my memory...

Perhaps that is because there was not 'something' in this combo which made you remember
 

That looks sweet how does it sound?

The most noticeable thing is that the K340 + Crack combo has an amazing sound stage, very holographic and spacious. The treble has great sparkle, the mid is neutral, a little bit cold but somehow smoother than K701. But the main weakness is its bass, I think the Crack can't drive the K340 to a decent level, the bass body is still not full, sub bass presents, but mid bass is not punchy also.
 
The combo is great for classical and acoustic, but it's definitely not suitable for basshead or those who love pop, rock or anything contains bass

 

[DefQon]

   
I also have a bit of thin carbon fibre flat plate which I could cut out to match and go over the alloy top plate which might also look a bit different.
 
 
 

 
I was and am still thinking of carbon fibering the top aluminium plate, but I'm not sure the carbon fiber decal can tolerate a few hours or constant daily use of on and off 40-55'C. Please do let me know if you pull it off on yours.
 
@K340 user: Bass depends on what K340 version you got, there are two version bass light and bass heavy.

 

[HolyCheese]

Is there anyway to lower the gain on this amp? It's hard to set it at low levels without volume imbalance.
 
I really wonder why they make all amps so extremely powerfull. I also have an O2 with the lowest gain possible and it doesn't get past 15%.
I have a feeling that it's best that average listening level is around 50% of volume on the knob.